Conventionally, an input device is known that aims at an intuitive and easy input operation along XYZ-axes, i.e. three dimensional (ref. patent document 1). The patent document 1 discloses: when an operator of the input device inserts the thumb into a ring portion and moves the thumb upward and downward, a finger stick portion moves upward and downward, allowing an input operation of various devices in Z-axis direction (ref. patent document 1). The above-mentioned conventional art allows the finger stick portion to easily move upward and downward when the operator moves the thumb upward and downward.